In the 1950s and 60s, the United States Army conducted armament evaluations and adopted selected armament cannons and ammunition families. As an example, the armament selected for the XM60 main battle tank (MBT) was the M68 cannon and the British 105 mmxc3x97617 mm ammunition suite. This ammunition suite was metallic cased using 70:30 cartridge case brass with a range of projectiles. As the 105 mmxc3x97617 mm ammunition suite matured, steel was substituted for the brass in cartridge case manufacture. Over time, the 105 mm cannon and ammunition suite was replaced by a 120 mm smoothbore cannon with its associated 120 mm ammunition suite. The 120 mm ammunition suite utilized combustible cartridge cases, manufactured by Armtec Defense Products of Coachella, Calif., in part because the combustible cartridge cases have very high operating pressures. At these high operating pressures, metallic cartridge cases plastically deform during firing and can result in cartridge cases unable to be extracted from the cannon""s firing chamber.
In the fall of 1999, 105 mm armament systems were evaluated as part of an infantry-centric doctrine to be used as a mobile assault cannon. The available 105 mm armament systems utilized the 20-year-old technology that had significant drawbacks. As an example, the prior technology could not adequately meet the strict weight restrictions of the air transportable mobile assault cannon. In addition, large caliber (e.g., 105 mm) metallic cartridge cases were not being domestically manufactured en masse at the time of the evaluation. In addition, the technology and designs for the 120 mm armament suite were not economically and adequately scaled down to a 105 mm armament suite, while maintaining the required performance criteria for the mobile assault cannon.
Under one aspect of the present invention, an ammunition round assembly having a combustible cartridge is provided. Under another aspect, an armament system comprising a firing device and an ammunition round assembly with a combustible cartridge case is provided.
In one embodiment, the ammunition round assembly comprises a cartridge body made of a combustible material consumed in combustion upon firing the ammunition round assembly. The cartridge body has a bottom end portion with a first retaining groove therein. A base is connected to the cartridge body""s bottom end portion. The base has a second retaining groove radially adjacent to the first retaining groove. The first and second retaining grooves define a locking groove between the base and the cartridge body. A retention member is positioned in the locking groove and engages the cartridge body and the base in the first and second retaining grooves to hold the cartridge body and the base together until the ammunition round assembly is fired. A projectile is adjacent to a top end portion of the cartridge body, and an attachment member releasably connects the projectile to the top end portion of the cartridge body.
In another embodiment, the ammunition round assembly has a combustible cartridge body, and a base is connected to a bottom end portion of the cartridge body. A projectile is positioned adjacent to the top end portion of the cartridge body. An attachment member connects the projectile and the cartridge body. The attachment member has a connection member releasably engaging the connection member on the top end portion of the cartridge body. The attachment member is configured to resist longitudinal motion of the projectile relative to the cartridge body.